Stepless transmission with disconnectable neutral seeking mechanism

ABSTRACT

A stepless transmission is provided with an input shaft (3004) having gear structure. A variator shaft (3014) including adjustable diameter pulleys (3018) and (3032) connected between the input shaft and the variator shaft. The variator alters the relative speeds of rotation between the input shaft and the variator shaft. An output shaft has gear structure (3054) that is operatively connected to the input shaft gear structure (3010) and the variator shaft gear structure (3042). The speed and direction of rotation of the output shaft (3048) is related to the difference between the tangential velocities of the input shaft gear structure and the variator shaft gear structure acting on the output shaft gear structure. Controls for the transmissions are also disclosed. The controls (3060) act to slow or speed the output of the transmission or to change the direction of the output. A braking system 3080) is provided which will act in either direction of rotation to return the transmission to the neutral position and to hold it there.

TECHNICAL FIELD

This invention relates generally to power transmissions, and moreparticularly to continuously variable power transmissions.

BACKGROUND ART

It is known to provide a continuously variable transmission in which therotation of an output shaft is dependent upon the difference between thespeeds of rotation of an input shaft and an alternate shaft. Andrus,U.S. Pat. No. 2,745,297 discloses a reversible speed changer with adrive shaft and a counter shaft. The drive shaft is connected to a sungear and the counter shaft is connected to a ring gear. A planetary gearsystem is connected between the ring gear and the sun gear. An outputshaft is operatively connected to the planetary gears such that rotationof the planetary gears will result in rotation of the output shaft. Thespeed of rotation of the output shaft is dependent upon the differencebetween the linear speeds of rotation of the sun gear and the ring gear.This difference in speeds of rotation can be controlled by a variablepower take-off which variably couples the counter shaft to the inputshaft. The transmission disclosed by Andrus produces relatively showspeeds and relatively low torque.

Gillade, U.S. Pat. No. 4,406,178, discloses a power transmission inwhich an input shaft is connected to a sun gear. The input shaft iscoupled to a driven shaft which is variably coupled to a disk on whichplanetary gears are mounted. The planetary gears mesh with the sun gearand with an output gear which is connected to an output shaft. Rotationof the output shaft is dependent upon the difference in linear speeds ofrotation of the disk and the sun gear.

DISCLOSURE OF INVENTION

It is an object of the invention to provide a stepless transmissionwhich will change from the neutral position to full speed and powerwithout interruption.

It is another object of the present invention to provide a steplesstransmission which will reverse the output direction without thenecessity of disconnecting the output temporarily from the power.

It is yet another object of the present invention to provide a steplesstransmission with high speed at the output.

It is another object of the invention to provide a stepless transmissionwith high torque at the output.

It is still another object of the invention to provide a steplesstransmission with an output control.

It is another object of the invention to provide a stepless transmissionwith a brake system.

It is yet another object of the invention to provide a steplesstransmission wherein variator means between an input shaft and variatorshaft regulates both output speed and direction by restraining variatorshaft rotation with variator shaft rotation being driven by a planetarygear system.

Continuously variable transmissions operate by transferring rotationalpower from an input shaft to an output shaft. The rotational speed thatis transferred to the output shaft is variable owing to a speed varyingsystem, presently referred to as the variator system. The variatorsystem may comprise a variable diameter pulley on each of the inputshaft and a variator shaft, so called because its rate of rotation iscontrolled by the input shaft through the variator system. The variatorsystem can comprise variable width pulleys on each of the input shaftand the variator shaft, and a pulley belt connected therebetween. Theinside surface of each face of the variable-width pulleys is typicallybeveled outward toward the center of each face, such that movement ofopposing faces toward one another will increase the effective diameterof the pulley, and movement of the faces away from one another willdecrease the effective diameter. The speed of rotation that istransferred from the input shaft to the variator shaft can be controlledby varying the effective diameter of one or both of the pulleys.

First gear means operatively connected to the input shaft meshes withthird gear means operatively connected to an output shaft. Second gearmeans operatively connected to the variator shaft also meshes with thethird gear means operatively connected to the output shaft. The rotationof the output shaft is dependent upon the difference between thetangential velocities of the first gear means and the second gear means.The difference in speeds of rotation can be continuously varied, in astepless fashion, by the variator system.

It has been found that improved transmissions will result if thetangential velocity of the first gear means is increased substantially.This will greatly increase the forward speeds which the transmission candeliver. The tangential velocity of the first gear means is increasedaccording to the invention by increasing the effective diameter of thefirst gear means. The first gear means has an effective diameter that ispreferably at least twice the diameter of the input shaft. A ring gear,for example, mounted to a drum connected to the input shaft will resultin the desired speeding. It is also possible to use a planetary gearsystem. This is a series of gears which are individually mounted to acarrier so as to be rotatable therewith. The planetary gears arepreferably evenly disposed about the axis of rotation of the carrier,which can be mounted to the end of the input shaft. Three gears disposedabout the axis of rotation and approximately 120° apart is a commonplanetary gear construction, and is used in the present invention,although others are possible. The effective diameter of the planetarygear construction, which is related to the distance of the gears fromthe axis of rotation of the carrier, is much greater than that of theinput shaft itself, and a net increase in the effective tangentialvelocity input shaft will result. Other gear means for increasing thetangential velocity of the first gear means can alternatively beprovided.

Increasing the tangential velocity of the first gear means will resultin a high forward (what is assumed to be forward) speed delivered to theoutput shaft. It is also desirable, however, to increase the torqueavailable at the output. This is made possible according to theinvention by reducing the tangential velocity of the second gear means.This is accomplished according to the invention by including a largeeffective diameter reduction gear with the second gear means. The largeeffective diameter reduction gear can be, among others, a simple gear, aring gear, or a planetary gear system and can be included with othergears to form the second gear means. In this manner, the angular speedof rotation of the second gear means is greatly reduced and theavailable torque is greatly increased.

Reduction of the speed of rotation of the second gear means willincrease torque but will decrease the speed available in the reverse(which is assumed to be reverse) drive direction, which occurs when thelinear tangential velocity of the second gear means exceeds that of thefirst gear means. A transmission might therefore have a very fastforward gear, with good torque characteristics, but with a slow reversegear. This condition is improved according to the invention byincreasing the speed of rotation from the input shaft to the variatorsystem, and thus to the variator shaft and the second gear means. Theincreased rotational speed is easily transferred through a pulley andbelt variator system with minimum slippage. A very high rotational speedis delivered to the variator shaft, which can be reduced as describedabove to produce a transmission with both high torque and high reversespeed characteristics. Increasing the input speed to the variator systemcan be accomplished by coupling the rotation of the input shaft fromlarger to smaller gear means, and then coupling these smaller gears,with increased angular velocities, to the variator system.

The relative dimensions of the first gear means and the second gearmeans are selected with regard to the desired output of thetransmission. If a high forward speed transmission is desired, withlittle concern for reverse speed, the effective diameter of the firstgear means can be increased several fold beyond that of the truediameter of the input shaft so that the tangential velocity of the firstgear means greatly exceeds that of the second gear means. Reverse can beobtained from this high forward speed embodiment by using a directionreversing gear at the output. Reverse could alternatively be provided byincreasing the tangential velocity of the second gear means. This can beaccomplished by decreasing the size of the reduction gear, or byincreasing the speed that is delivered from the input shaft to thevariator, and thus to the variator shaft and the second gear means. Thevariator can also be adjusted to increase the relative tangentialvelocity of the second gear means with respect to the first gear means.

Neutral is obtained when the tangential velocity of the first gear meansand second gear means, as seen by the third gear means, are equal. Theeffective diameter of the first gear means, the degree to which therotational speed of the input shaft is increased and coupled to thevariator, the ratio of rotational speed transferred to the variatorshaft by the variator, the reduction means included with the second gearmeans, and the effective diameter of the second gear means will all beinterrelated and must be selected for the purpose at hand. In general,where the first gear means is a sun gear, it is preferable that thetangential velocity of the sun gear be at least 1.5 times the tangentialvelocity of the ring gear, which is rotating in the opposite direction.Where the first gear means is a ring gear and the second gear meansconsists of planetary gears on a carrier, it is preferable that thetangential velocity of the ring gear should be at least twice that ofthe planetary system, which will normally be rotating in the samedirection. Where the first gear means is a system of planetary gears ona carrier and the second gear means is a sun gear, it is desirable thatthe tangential velocity of the sun gear be at least twice that of thetangential velocity of the planetary system, which is rotating in thesame direction. Where the first gear means is a system of planetarygears on a carrier and the second gear means is a ring gear, it isdesirable that the tangential velocity of rotation of the ring gear beat least twice that of the tangential velocity of rotation of theplanetary system, which is rotating in the same direction.

It is desirable to provide a control system which will control thedirection and speed of rotation of the output shaft, and which will findand retain the neutral position. The control is operatively connected tothe variator system such that it will be responsive to humanmanipulation or to sensing devices monitoring operation characteristicssuch as engine speed and the like. The control acts to adjust the ratioof angular rotational speed that is transferred from the input shaft tothe variator shaft.

The rotation of the output shaft can be operatively connected to thevariator system by a brake or neutral servo system according to theinvention. The operative connection is such that rotation of the outputshaft in either direction will act to adjust the variator system, as byincreasing or decreasing the effective diameter of a variable widthpulley, to adjust the relative speeds of rotation between the inputshaft and the variator shaft so as to equalize the rates of rotation ofthe first gear means and the second gear means. This action will slowthe transmission until the neutral position has been obtained. It ispreferable to provide a selective coupling of the brake to the outputshaft, such that the output shaft is freely rotatable when the couplingis not applied. The coupling is preferably a friction pad whichfrictionally engages the output shaft, and which is operativelyconnected through the brake to the variator system.

There are shown in the drawings embodiments which are presentlypreferred, it being understood, however, that the invention is notlimited to the precise arrangements and instrumentalities shown,wherein:

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a side elevation, partially broken away, of a transmissionaccording to the invention.

FIG. 2 is a side elevation, partially broken away, of a transmissionaccording to the invention.

FIG. 3 is a side elevation, partially broken away, of a transmissionaccording to the invention.

FIG. 3a is a side elevation, partially broken away, of a transmissionaccording to the invention.

FIG. 4 is a side elevation, partially broken away, of a transmissionaccording to the invention.

FIG. 5 is a side elevation, partially broken away, of a transmissionaccording to the invention.

FIG. 6 is a side elevation, partially broken away, of a transmissionaccording to the invention.

FIG. 7 is a side elevation, partially broken away, of a transmissionaccording to the invention.

FIG. 8 is a side elevation, partially broken away of a transmission, avariator system, and a control according to the invention.

FIG. 9 is a side elevation, partially broken away, of a transmissionaccording to the invention.

FIG. 10 is a side elevation, partially broken away, of a transmission, avariator system, and a control according to the invention.

FIG. 11 is a side elevation, partially broken away, of a transmissionaccording to the invention.

FIG. 12 is a cross-section taken along line A--A in FIG. 11.

FIG. 13 is a perspective view, partially broken away, of a transmissionand control according to the invention.

FIG. 14 is a side elevation, partially broken away, of a controlaccording to the invention.

FIG. 15 is a cross-section taken along line B--B in FIG. 14.

FIG. 16 is a partial side elevation, partial schematic of a controlaccording to the invention.

FIG. 17 is a perspective diagrammatic view of a neutral-seeking servomechanism of the invention.

MODES OF CARRYING OUT THE INVENTION

Referring to FIG. 1, there is shown a stepless transmission according tothe invention. The transmission 20 has a housing 22 through which aninput shaft 24 is rotatably mounted. The input shaft 24 is rotated by amotor or other suitable power source (not shown). A drum 28 within thehousing 22 may include a depression 26. The drum 28 is fixed to anoutput shaft 30, which is rotatably mounted through the housing 22. Theinput shaft 24 may be rotatably supported in the depression 26. An inputbeveled gear 32 is affixed to the input shaft 24 and meshes with twobeveled gears 34, 36 which are rotatably mounted to an inside surface ofthe drum 28. A fourth tubular beveled gear 40 is mounted about the inputshaft 24 so as to be freely rotatable with respect thereto.

A variator system comprises a variable width pulley 42 affixed to theinput shaft 24 preferably outside of the housing 22. Oil within thehousing 22 will not then affect the operation of the pulley. Thevariable width pulley 42 includes opposing beveled pulley faces 44, 46which are movable with relation to one another so as to vary thedistance between them. In this manner the effective pulley diameterpresented to a belt 50 can be increased or decreased. Biasing means canbe located within a housing 52 for balancing the pulley belt 50. Thebiasing means can be a spring 54.

A variator shaft 58 is rotatably mounted through the housing 22. Thevariator shaft 58 has a variable width pulley 60 mounted thereon. Thevariable width pulley 60 includes beveled faces 66 and 68. The pulleybelt 50 engages the pulley 60 such that speed of the input shaft 24 isused to control variator shaft 58. The variator shaft 58 may be tubularin construction such that a control arm 64 can extend therethrough, Thecontrol arm 64 acts on the variable width pulley 60 to alter thedistance between beveled pulley faces 66, 68 to vary the effectivediameter of the pulley 60.

The control arm 64 can be operatively connected to the pulley face 66,for example. A housing 65 on the variator shaft 58 can be used toconnect the control arm 64 to the beveled face 66 of the pulley 60. Thepulley face 66 can be slidably mounted on the variator shaft 58 throughadjustment of opposing pulley faces. The opposing pulley face 68 in thisembodiment might be fixed to the variator shaft 58. The variator pulleysystem alters the relative speed of rotation between the input shaft 24and the variator shaft 58. Movement of the control arm 64 inwardly oroutwardly will move the beveled face 66 of the variable pulley 60inwardly or outwardly to vary the effective diameter of the pulley 60.Biasing 54 acting on the pulley 42 will automatically adjust this pulleyto the proper spacing for a given effective diameter of the pulley 60.The pulley belt 50 being of a fixed length, it can be seen thatincreasing the effective diameter of the pulley with respect to thepulley 42 will decrease the rotational speed of the variator shaft 58with respect to the input shaft 24.

A variator gear 74 is affixed to the variator shaft 58 within thehousing 22. The gear 74 meshes with a gear 78 which is fixed to thefourth gear 40. The gear 78 is preferably larger in diameter than thegear 74 such that gear reduction occurs from the gear 74 to the gear 78.This reduction will deliver an increased torque to the fourth gear 40.The relative diameters of the gears 74 and 78 can be adjusted to varythe torque and rotational speed of the fourth gear 40. Decreasing thediameter of the gear 78 will generally increase the speed available atthe fourth gear 40, but will result in a decrease in the torque.

The direction and speed of rotation of the output shaft 30 will dependupon the relative tangential velocities of rotation of the fourth gear40 with respect to the input beveled gear 32. When the input gear 32 isrotating at a speed faster than the fourth gear 40, the beveled gears34, 36 will be carried by this gear, and the drum 28 and output shaft 30will rotate in a similar direction. The speed of rotation will beproportional to the difference in linear speeds of rotation between theinput beveled gear 32 and the fourth gear 40. The diameter of the inputbeveled gear 32, being larger than the input shaft 24, will greatlyincrease the tangential velocity of the input. The speed of rotation ofthe fourth gear 40 is controlled through the control arm 64 whichadjusts the variator pulley system through movement of the beveled face65 of the variable pulley 60. This movement increases or decreases therotational speed of the variator shaft 58, the variator gear 74, andthus the gear 78 and fourth gear 40. Should the fourth gear 40 be causedto rotate at a greater speed than the input gear 32, the beveled gears34, 36 will follow the fourth gear 40 and the drum 28 and the outputshaft 30 will rotate in a similar direction. The speed of rotation willagain be proportional to the difference between the speeds of rotationof the input gear 32 and fourth gear 40. Equality in tangentialvelocities of the input beveled gear 32 and the fourth gear 40 willresult in a neutral position in which the beveled gears 34, 36 followneither the input gear 32 nor fourth gear 40. A brake or neutral controlsystem may be provided to prevent drifting of the output shaft 30 in theneutral position, which can occur due to vibrations acting on thetransmission. The brake system can include a brake pad 82 which isapplied to a raised friction surface 80 on the output shaft 30. Thebrake pad 82 will lock the output shaft 30 in the neutral position. Thebrake pad 82 is preferably coupled to the control arm 64 by suitablelinkage means such that application of the brake pad to the frictionsurface 80 will occur only when the control arm is in, or desired to bein, the neutral position. The operation of control and brake accordingto the invention is described elsewhere in the specification.

Transmissions according to the invention can function with power inputson alternative shafts. The transmission shown in FIG. 1 can functionwith the power input to the transmission moved to the shaft 30. Theoutput could then be taken from either of the shafts 24 or 58. Thevariator system should in this embodiment be moved to the opposite sideof the transmission to act on the shaft 30 and shaft 58. Means couldalso be provided to increase the tangential velocity from the inputshaft to the variator system. The means would include gearing systems.

The transmission shown in FIG. 2 provides very high speed and torque atthe output. The input can be taken on a shaft 98 which is rotatablymounted through a housing 100. A drum 103 fixed to the input shaft 98has an internal ring gear 102. A speeding external ring gear 104 is alsofixed to the drum 103 on the shaft 98. The speeding ring gear 104 mesheswith a second speeding gear 106, which is preferably tubular androtatably mounted about a variator shaft 130. The variator shaft 130 isrotatably mounted through the housing 100. The second speeding gear 106is generally of smaller diameter than the speeding external ring gear104 such that the second speeding gear 106 rotates at a greater angularspeed than the input shaft 98. A third speeding gear 112 is fixed to thespeeding gear 106 and meshes with a tube gear 114 which is rotatablymounted about the input shaft 98 and through the housing 100. The tubegear 114 is generally of a smaller diameter than the third speeding gear112 such that a further increase in rotational speed occurs from thegear 112 to the tube gear 114. The tube gear 114 is fixed to a variatorsystem pulley 118. A pulley belt 124 operatively connects the pulley 118with a second variator pulley 128 which is mounted to the variator shaft130. The variator shaft 130 can be tubular such that a control arm 132can extend therethrough.

The control arm 132 can vary the width of the pulley 128 by moving abeveled face 134 of the pulley 128 inwardly or outwardly with respect toan opposing beveled face 136. The pulley face 134 is longitudinallymoveable on the variator shaft 130. The control arm 132 is operativelyconnected to a housing 133 which is mounted to the beveled face 134 ofthe pulley 128. Movement of the pulley face 134 with respect to theopposing face 136 will vary the effective diameter which the pulley 128presents to the pulley belt 124. In this manner, the rotational speed ofthe variator shaft 130 with respect to the input shaft 98 can be alteredby manipulation of the control arm 132.

The variator shaft 130 includes a variator gear 140 which meshes with atubular reduction gear 142. The tubular reduction gear 142 preferably isof larger diameter than the variator gear 140, and a reduction therebyoccurs which increases the torque available at this gear. A tubular sungear 148 is fixed to the tubular reduction gear 142. The sun gear 148and reduction gear 142 are rotatably mounted about an output shaft 150.The output shaft 150 is rotatably mounted through the housing 100 andhas fixed thereto at its end within the housing 100 a planetary carriersupport 154. The output shaft 150 includes a projection 152 at its endwithin the housing 100. The projection 152 can be rotatably secured tothe drum 103, as in the groove 153. The carrier 154 has planetary gears156 rotatably mounted thereon which mesh with and between the sun gear148 and the internal ring gear 102.

The difference in tangential velocities of the oppositely rotating ringgear 102 and sun gear 148 will determine the direction and speed ofrotation of the output shaft 150. The speeding system exemplified bygears 104, 106, 112 and 114 delivers a high rotational speed to thevariator system and thus to the variator shaft. This speed can bereduced through the reduction gear 142 to deliver high torque. Greaterreverse speed and lower torque can be provided by reducing the diameterof the reduction gear 142 relative to the diameter of the variator gear140. The transmission, in any case, delivers high speed and torque tothe output. The input power could also alternatively be placed on theshaft 150 and the output taken from the shaft 98. The variator systemwould then be operatively connected between the variator shaft 130 andthe shaft 150.

Another transmission according to the invention is shown in FIG. 3. Aninput shaft 202 is rotatably mounted through a housing 204 and has fixedat its end within the housing 204 a sun gear 206. An output shaft 208 isrotatably mounted through the housing 204 and has affixed to the endwithin the housing a drum 210 with an internal ring gear 211. The inputshaft 202 preferably has a projection 212 at its end within the housing204 which rotatably supports the input shaft 202 in a depression 214formed in the drum 210. A variator shaft 220 is rotatably mountedthrough the housing 204. A variator system (as previously described) maybe mounted between the input shaft 202 and variator shaft 220 to drivethe variator shaft 220 through rotation of the input shaft 202. Thevariator system would preferably include variable width pulleys andpulley belts. A control arm 222, which may extend through the variatorshaft 220, may be used to adjust the variator pulleys to alter therelative speeds of rotation between the input shaft 202 and variatorshaft 220. The variator shaft 220 has a variator gear 226 which mesheswith a reverse direction gear 232 on a shaft 230 which is rotatablymounted within the housing 204. A tubular reduction gear 236 isrotatably mounted about the input shaft 202 and meshes with the reversedirection gear 232. Planetary gears 240 are rotatably mounted on thereduction gear 236 and mesh with and between the sun gear 206 and thering gear 211. The reverse direction gear 232 changes the direction ofrotation of the reduction gear 236 so that the direction of rotation isthe same of the sun gear 206.

The direction and speed of rotation of the ring gear 211 and thus theoutput shaft 208 is dependent upon the relative tangential velocities ofthe rotating sun gear 206 and the axis of the planetary gears 240. Whenthe sun gear 206 is rotating at a much greater tangential velocity thanthat of the planetary carrier 236 or the axis of the planetary gears240, these gears and the ring gear 211 will follow the sun gear 206. Theoutput shaft 208 will then rotate at a speed that is related to thedifference in rotational speeds between the sun gear 206 and planetarygears 240. Alternatively, input power could be applied to either of theshafts 208, 220 or 230.

The need for a reverse direction gear such as the gear 232 in theembodiment of FIG. 3 can be eliminated with the incorporation of a chaindrive system as shown in FIG. 3a. FIG. 3a depicts a transmission whichis in most respects identical to that in FIG. 3. Input shaft 202a isrotatably mounted through a housing 204a and has at its end within thehousing 204a a sun gear 206a. An output shaft 208a is rotatably mountedthrough the housing 204a and has fixed thereto, at its end within thehousing, a drum 210a with an internal ring gear 211a. The input shaft202a has a projection 212a which is rotatably secured within adepression 214a in the drum 210a. A variator shaft 220a is rotatablymounted through the housing 204a and may have a control arm 222aextending therethrough with which to control a variator system (notshown). The variator shaft 220a has thereon a sprocket 226a which takesthe place of the variator gear 226 in FIG. 3. A reduction sprocket 236a,with a larger diameter than the variator sprocket 226a carries planetarygears 240a, which are rotatably mounted thereto. A chain 230a isconnected between the variator sprocket 226a and the reduction sprocket236a. The direction of rotation of the variator sprocket 226a and thereduction sprocket 236a is the same, and a direction reversing gear,such as the gear 232 in FIG. 3, can be omitted. Power in this embodimentcould alternatively be applied at the shafts 220a or 202a.

Still another embodiment of the invention is shown in FIG. 4. An inputshaft 290 is rotatably mounted through a housing 294. A drum 302 with aninternal ring gear 298 is mounted at the end of the input shaft 290within the housing 294. Planetary gears 300 are rotatably mounted to theperiphery of the back side of the drum 302, facing the input shaft 290.A stationary internal ring gear 208 is fixed to the interior of thehousing 294 and meshes with the planetary gears 300. A tubular sun gear312 is rotatably mounted about the input shaft 290 and meshes with theplanetary gears 300. A high rotational speed is imparted to theplanetary gears 300 by rotation of the relatively large diameter drum302 and this speed is thereby transferred to the tubular sun gear 312.The tubular sun gear 312 preferably extends through the housing 294. Avariator system (not shown) is connected between the speeded tubular sungear 312 and a variator shaft 314, which is rotatably mounted throughthe housing 294. A movable control arm 318 can extend through thevariator shaft 314 to control a variable width pulley in the variatorsystem, as previously described. A variator gear 320 is fixed to thevariator shaft 314 within the housing 294. The variator gear 320 mesheswith a tubular reduction gear 322 which is rotatably mounted about anoutput shaft 324. The output shaft 324 is rotatably mounted through thehousing 294. A tubular sun gear 328 is fixed to the reduction gear 322and thus also is rotatably mounted about the output shaft 324. Theoutput shaft 324 has at its end within the housing 294 a planetary gearcarrier 330. Planetary gears 334 are rotatably mounted to the planetarycarrier 330 and mesh with and between the ring gear 298 and the sun gear328.

The speed and direction of rotation of the output shaft 324 will dependupon the difference in the tangential velocities between the oppositelyrotating ring gear 298 and the sun gear 328. The speed and direction canbe changed by adjusting the variator system through the control arm 318to alter the speed of rotation of the variator gear 320 and thus thereduction gear 322 and the sun gear 328. High speed is generated throughthe speeding system of planetary speeding gears 300 and the tubularspeeding sun gear 312. Speed, rather than torque, is transmitted throughthe variator system, which cannot transmit high torque owing to slippageof the belt. High torque is obtained, however, via the reduction whichtakes place between the variator gear 320 and the reduction gear 322.

Yet another embodiment of the invention is shown in FIG. 5. An inputshaft 380 is rotatably mounted through a housing 384. The input shaft380 has at its end within the housing 384 a drum 386. The drum 386 hasan internal ring gear 388. A variator shaft 390 is driven by a sun gear424. Variator shaft 390 is restrained from spinning freely and its rateof rotation is controlled by its adjustable speed linkage to input shaft380 by a variator system. A variator system may include a variable widthpulley 392 on the input shaft 380 and a variable width pulley 394 on avariator shaft 390 rotatably mounted through the housing 384. A pulleybelt 396 is connected between the pulleys 392 and 394. The variatorshaft 390 may be tubular in construction such that a control arm 398 canextend therethrough. The control arm 398 engages a housing 400 on abeveled face 402 of the pulley 394. Movement of the control arm 398 willmove the beveled face 402 inward or outward with respect to an opposingbeveled face 404 of the pulley 394 to vary the effective diameter ofthis pulley. This movement will vary the rotational speed that istransferred between the pulley 392 and the pulley 394. Biasing meanssuch as a spring can be provided in a housing 406 on the input shaft 380to balance the force of the pulley belt 396. A variator gear 410 isprovided on the variator shaft 390 within the housing 384. The variatorgear 410 meshes with a relatively large diameter tubular reduction gear414. The tubular reduction gear 414 is rotatably mounted about an outputshaft 420 which is rotatably mounted through the housing 384. A tubularsun gear 424 is fixed to the reduction gear 414 and also is rotatableabout the output shaft 420. A planetary carrier 426 is provided at theend of the output shaft 420 within the housing 384 and within the drum386. The planetary carrier 426 has planetary gears 430 mounted thereon.The planetary gears 430 mesh with and between the tubular sun gear 424and the internal ring gear 388.

The speed and direction of rotation of the output shaft 420 will bedependent upon the difference between the tangential velocities of ringgear 388 and the tubular sun gear 424. The tangential velocity of theinput shaft 380 is greatly increased by the relatively large diameterinternal ring gear 388. This transmission will therefore have a highforward speed. High torque is nonetheless obtained by the reductionwhich takes place from the variator gear 410 to the reduction gear 414.

This embodiment clearly demonstrates another feature of the invention.When the variator pulley 392 is relatively small and the variator pulley394 is relatively large, the pulley 394 tries to rotate the input shaftfaster in the same direction but cannot. The effect is to slow down thetubular reduction gear 414 and the tubular sun gear 424. Torque createdby the reduction (slowing down) of the sun gear 424 is transferredthrough the reduction gear 414, the variator gear 410, and through thevariator system and pulley belt 396 back to the input shaft 380. It ispossible to brake the variator gear by suitable brake means which caninclude a raised friction surface 440 on the variator shaft 390. A brakepad 444 can be applied to the friction surface 440 with adjustable forcefor varying the degree of braking. The friction pad 444 can be actedupon by suitable control means which can be pneumatic or hydraulic inorigin as through the conduit 448.

Yet another embodiment of the present invention is shown in FIG. 6. Aninput shaft 470 is rotatably mounted through a housing 474. The inputshaft 470 has at its end within the housing 474 a planetary gear carrier478. The carrier 478 has rotatably mounted on the periphery of its sidesfacing the input shaft 470 a plurality of speeding planetary gears 480.The speeding planetary gears 480 mesh with a stationary internal ringgear 482 fixed to the interior of the housing 474. A tubular speedingsun gear 484 is rotatably mounted about the input shaft 470 and mesheswith the speeding planetary gears 480. The tubular speeding sun gear 484extends through the housing 474 where it connects to the variator system(not shown) such as to a variable width pulley. Input rotational speedfrom the input shaft 470 is increased by the speeding planetary gears480 and speeding sun gear 484 to the variator system.

High rotational speed is transferred through the variator system to avariator shaft 488. The variator shaft 488 is rotatably mounted throughthe housing 474. The variator shaft 488 can be tubular in constructionand can have extending therethrough a movable control arm 490. Thecontrol arm 490 can be used to control the transfer of rotational speedthrough the variator system (not shown) to the variator shaft 488. Thiscan be accomplished, as previously described, by adjusting the widthbetween opposing faces of a variable width pulley, or by other suitablemeans. A variator gear 494 is fixed to the variator shaft 488 within thehousing 474 and meshes with a rotational direction reversing gear 498which is mounted to a shaft 502 rotatably mounted within the housing298. The direction reversing gear 498 meshes with an external ring gear505 on a drum 506 which can be rotatably mounted about an output shaft510. The output shaft 510 is rotatably mounted through the housing 474and has at its end within the housing 474 a sun gear 514. Powerplanetary gears 518 are rotatably mounted to the carrier 478 on the sideopposite the input shaft 470. The power planetary gears 518 mesh withand between an internal ring gear 507 on the drum 506, and the sun gear514.

The speed and direction of rotation of the output shaft 510 is dependentupon the difference in the tangential velocities between the axis of thepower planetary gears 518 and the internal ring gear 507 on the drum506. High speed is generated by means of the speeding planetary gears480 and speeding sun gear 484. High speed can be transferred through thevariator system without slippage. The high speed output from thevariator system is reduced at the external reduction ring gear 505 onthe drum 506 to increase the available torque. High speed is generatedfor forward drive due to the positioning of the planetary gears 518about the periphery of the planetary carrier 478. This peripheralpositioning provides in sum a relatively large diameter input whichincreases the effective tangential velocity of the axis of planetarygears 518. The transmission therefore provides both very high speed aswell as high torque at the output shaft 510. It is possible to providefurther reduction gears between the variator shaft 488 and the externalreduction ring gear on the drum 506.

Another embodiment of the present invention is shown in FIG. 7. An inputshaft 570 is rotatably mounted through a housing 574. The input shaft570 has at its end within the housing 574 a drum 578. The drum 578 has afirst internal ring gear portion 580 about the input shaft 570. Thefirst ring gear portion 580 meshes with planetary gears 584 which arerotatably mounted to the housing 574. The planetary gears 584 also meshwith a tubular speeding sun gear 590. The speeding planetary gears 584and sun gear 590 increase the angular speed of rotation which isdelivered to the variator system. The variator system can include avariable width variator pulley 592 on the input shaft 570. Power istransferred from the pulley 592 to a variable width pulley 594 by apulley belt 595. The pulley 594 is mounted on a variator shaft 598 whichis rotatably mounted through the housing 574. The variator shaft 598 canbe tubular in construction such that a control arm 604 can extendthrough it to connect to the variator system. The control arm 604 can beconnected to a face of the pulley 594 to control the spacing between theopposing faces of the variable width pulley 594, and thereby to controlthe speed transferred through the variator system. A variator gear 602is fixed to the variator shaft 598 within the housing 574 and mesheswith a tubular reduction gear 608 rotatably mounted about an outputshaft 610. The output shaft 610 is rotatably mounted through the housing574. A tubular sun gear 614 is fixed to the reduction gear 608, and isrotatably mounted about the output shaft 610 such that the speed ofrotation of the sun gear is controlled by the variator pulley ratio. Theoutput shaft 610 has at its end within the housing 574 a planetary gearcarrier 618. Planetary gears 620 are rotatably mounted about theperiphery of the side of the carrier 618 facing the output shaft 610. Asecond internal ring gear portion 624 is located on a side of the drum578 opposite the input shaft 570. The planetary gears 620 mesh with andbetween the sun gear 614 and the second internal ring gear portion 624.

The direction and speed of rotation of the output shaft 610 will dependupon the difference in the tangential velocities of the second ring gearportion 624 and the sun gear 614. High rotational speed is generatedfrom the input shaft 570 through the first ring gear portion 580,speeding planetary gears 584 and tubular speeding sun gear 590. Highspeed can be transferred through the variator system with a minimum ofslippage. High torque is obtained from this high speed output from thevariator system through the reduction gear 608. High drive speed isobtained by the relatively large diameter second internal ring portion,which greatly increases the tangential velocity of the input shaft 570.

Another embodiment of the invention is shown in FIG. 8. An input shaft780 is rotatably mounted through a housing 784. A variator shaft 790receives power through a variator system which can be a pulley and beltsystem as previously described. A variator gear 794 is fixed to thevariator shaft 790 and meshes with a direction reversing gear 796 whichis rotatably mounted to the housing 784. A brake pad 791 can be appliedto the variator shaft 790, preferably at a raised friction surface 792on the variator shaft 790. The brake pad 791 can be controlled by asuitable control means, such as the pneumatic signal supply conduit 793.The control means can be responsive to the torque on the shaft 790. Thedirection reversing gear 796 meshes with a tubular reduction gear 806.The reduction gear 806 is rotatably mounted about an output shaft 810.The output shaft 810 is rotatably mounted through the housing 784.

A drum 814 is mounted at the end of the input shaft 780 within thehousing 784 and opens toward and surrounds the end of the output shaft810. A drum 818 is fixed to the end of, and opens toward, the outputshaft 810, within the drum 814. A projection 820 on the end of theoutput shaft 810 can rotatably rest in a groove 824 formed in the drum814 to rotatably secure the output shaft 810 and drum 818 in place. Aninternal ring gear 819 on the drum 818 meshes with planetary gears 828.The planetary gears 82 are rotatably mounted to a planetary carrier 830has a central opening 832 which allows passage of the output shaft 810therethrough. A tubular sun gear 834 is rotatably mounted about theoutput shaft 810 within the drum 814 and has a neck portion 835 whichextends outward through the central opening 832. The neck portion 835 isfixed to the reduction gear 806. The planetary gears 828 face theinterior of the drum 814 and are circumferentially disposed about thesun gear 834. The planetary gears 828 mesh with and between the sun gear834 and the internal ring gear 819.

The speed of rotation of the output shaft 810 will depend upon thedifference in the tangential velocities of the planetary gears 828 andthe tubular sun gear 834, which rotate in the same direction. The largediameter drum 814 and the planetary gears 828 increases the tangentialvelocity of the input shaft 780. The reduction gear 806 increases thetorque available from the transmission. It is possible to interchangethe power supply to the shafts so that power, for example, could beapplied to what is presently the output shaft 810 and taken from theinput shaft 780.

Another embodiment of the present invention is shown in FIG. 9. A firstvariator shaft 870 is rotatably mounted through a housing 874. A drum878, having an internal ring gear 880, is mounted to the end of thefirst variator shaft 870 within the housing 874. A second variator shaft882 is rotatably mounted through the housing 874. Input velocity istransferred from an input shaft 910 to the first variator shaft 870 orto the second variator shaft 882 through a variator system which can bea pulley and belt system as previously described, for as much as a tenfold increase in speed range. A variator gear 884 is fixed to the secondvariator shaft 882 within the housing 874. The variator gear 884 mesheswith a tubular reduction gear 890. The tubular reduction gear 890 isrotatably mounted about an output shaft 896. The output shaft 896 isrotatably mounted through the housing 874. Planetary gears 902 arerotatably mounted to a planetary carrier 906 which is fixed to the endof the output shaft 896 within the housing 874. A tubular sun gear 900is rotatably mounted about the output shaft 896 and fixed to thereduction gear 890. The sun gear 900 meshes with and between thecircumferentially arranged planetary gears 902, which in turn mesh withthe internal ring gear 880.

The input shaft 910 is rotatably mounted through the housing 874 andhas, within the housing, a differential system which can be used as analternative to the variator system for transferring power from the inputshaft 910 to the first variator shaft 870 and the second variator shaft882. The differential system includes a first beveled gear 912 rotatablymounted about the shaft 910. A tandem gear 914 is fixed to the firstbeveled gear 912 and meshes with a gear 920 which is fixed to the firstvariator shaft 870. A second beveled gear 924 is rotatably mounted aboutthe input shaft 910 and has a tandem gear 928 fixed to it. The tandemgear 928 meshes with a second variator gear 930 fixed to the secondvariator shaft 882. A third beveled gear 932 and a fourth beveled gear934 are rotatably mounted about pins 938, 940, respectively, which arefixed to the input shaft 910. The third beveled gear 932 and fourthbeveled gear 934 each mesh with both the first beveled gear 912 and thesecond beveled gear 924.

Input power can be transferred to the variator shafts 870 and 882through the action of the beveled gear differential. Brake means such asbrake pad 944 can be applied to the first variator shaft 870 preferablyat a raised friction surface 946 to slow or lock the gear 920 in place.This will lock the tandem gear 914 in place. Rotation of the input shaft910 will then rotate the pins 938, 940 and cause the third gear 932 andfourth gear 934 to translate about the first beveled gear 912 and rotateabout the pins 938 and 940, respectively. The second beveled gear 924and its associated tandem gear 928 will be driven by the third gear 932and fourth gear 934. Rotation of the tandem gear 928 drives the secondvariator gear 930 and the second variator shaft 882. This in turn drivesthe variator gear 884 and thus the reduction gear 890 and the tubularsun gear 900. Power input at the input shaft 910 is thereby delivered tothe sun gear 900. This will drive the output shaft 896, through itsassociated planetary gears 902, about the internal ring gear 880, whichhas been slowed or locked by the brake 944. The direction of rotation ofthe output shaft 896 will be the same rotational direction as that ofthe tubular sun gear 900.

Alternatively, the second variator shaft 882 can be slowed or locked bybrake means such as a brake pad 950. The brake pad 950 preferably actson a raised friction surface 952 on the second variator shaft 882. Thiswill slow or lock the second beveled gear 924 in place, as well as thetubular sun gear 900. Rotation of the input shaft 910 will rotate pins938, 940, and thus translate the third beveled gear 932 and fourthbeveled gear 934 about the slowed or locked second beveled gear 924.This motion of the third and fourth beveled gears 932 and 934 will carrythe first beveled gear 912. Rotation of the associated tandem gear 914will rotate the gear 920 on the first variator shaft 870, which in turnwill rotate the drum 878 and the ring gear 880. The tubular sun gear 900being fixed by the locked variator shaft 882, the planetary gears 902will follow the internal ring gear 880 as it rotates, thereby causingthe output shaft 896 to rotate in a similar direction. This will deliverpower available at the input shaft 910 to the output shaft 896. Thisembodiment of the invention allows the user to transfer power to thevariator shaft through the spider gear system whenever the variatorsystem between the input shaft 910 and variator shafts 870 and 882 doesnot function. The direction and speed of the transmission can then becontrolled by the application of brakes 944 and 950.

Input power can also be divided from the input shaft 910 to each of thevariator shafts 870 and 882 by the variator system. This system can be apulley and belt system as previously described. The variator systemincludes a variable width pulley 980 on the first variator shaft 870 anda variator width pulley 982 on the second variator shaft 882. A doublepulley 984 on the input shaft 910 engages pulley belts 986, 988 totransfer speed control from the input shaft 910 to the first variatorshaft 870 and the second variator shaft 882, respectively. The spacingbetween faces of the pulleys can be adjusted as by a control arm 990 toalter the relative effective diameter of the pulleys. This will controlthe relative speeds of rotation between the two variator systems.

The speed and direction of rotation of the output shaft 896 is dependentupon the difference between the tangential velocities of the internalring gear 880 and the tubular sun gear 900, which is related to therelative speeds of rotation of the two variator shafts. This differencein tangential velocity can be adjusted by the application of the brakes944 and 950, or by adjusting the effective diameter of the variablewidth pulleys 980 and 982. Adjustment can be effected on the variatorsystem by a control arm 990 acting to adjust the spacing between facesof any of the pulleys. A brake system for each variator shaft can alsobe provided to adjust the speed. The large diameter ring gear 880effectively increases the tangential velocity of the first variatorshaft 870. This will cause the planetary gears 902 to follow theinternal ring gear 880 at a relatively rapid rate. A high speed outputcan then be taken from the output shaft 896 in this direction ofrotation. This high speed output is accompanied by high torque owing tothe reduction which takes place from the variator gear 884 to the largediameter reduction gear 890.

In FIG. 10 there is shown a transmission in which an input shaft 974 isrotatably mounted through a housing 978. The input shaft 974 has fixedat its end within the housing 978 a drum 982 with an internal ring gear984. A first variator shaft 986 is rotatably mounted through the housing978. The first variator shaft 986 has a sprocket 988 fixed theretowithin the housing which engages a chain 990. The chain 990 engages atubular reduction sprocket 994 with a larger diameter than the sprocket988. The tubular sprocket 994 is rotatably mounted about an output shaft996 which is rotatably mounted through the housing 978. The output shaft996 has at its end within the housing 978 a planetary carrier 998. Theplanetary carrier 998 has planetary gears 1000 rotatably mountedthereon. A tubular sun gear 1004 is fixed to the tubular reductionsprocket 994 and rotatably mounted about the output shaft 996. Thetubular sun gear 1004 is fixed to the tubular reduction sprocket 994 androtatably mounted about the output shaft 996. The tubular sun gear 1004meshes with and between the planetary gears 1000 which are preferablydisposed circumferentially about the sun gear 1004. The drum 982 has anexternal ring gear 1008 which meshes with a second variator gear 1010 ona second variator shaft 1012. The second variator shaft 1012 isrotatably mounted through the housing 978. The larger diameter externalring gear 1008 greatly speeds the rotation of the second variator gear1010. Power is transferred from the speeded second variator shaft 1012to the first variator shaft 986 by a variator system, which can be apulley and belt system. This speed is reduced from the first variatorshaft 986 to the tubular sun gear 1004 by the reduction which takesplace between the first variator gear 990 and the tubular reduction gear994.

The speed and direction of rotation of the output shaft 996 will dependupon the difference between the tangential velocities of rotation of thelarge diameter internal ring gear 984 and the tubular sun gear 1004.This embodiment offers a high forward speed owing to the greatlyincreased tangential velocity seen at the input as a result of the largediameter of the internal ring gear 984. High speed is transferredthrough the variator system. The high speed is generated from the inputrotational speed by the action of the large diameter external ring gear1008 on the much smaller variator gear 1010. High torque is producedform the reduction which takes place between the first variator gear 990and the tubular reduction gear 994.

Another embodiment of the invention is shown in FIGS. 11-12 wherein aninput shaft 1030 has a sun gear 1038 fixed at its end. The sun gear 1038meshes with inside galaxial gears 1042 which are rotatably mounted on agalaxial carrier 1046. Outside galaxial gears 1050 also are rotatablymounted to the galaxial carrier 1046 and mesh with and between aninternal ring gear 1054 and the inside galaxial gears 1042. An outputshaft 1060 is fixed to the galaxial carrier 1046 opposite the galaxialgears. The internal ring gear 1054 is on a drum 1055 which is rotatablymounted about the output shaft 1030. A variator shaft 1064 has avariator gear 1068. The variator gear 1068 meshes with an external ringgear 1070 on the drum 1055. A variator system (not shown) can be used tocontrol the speed of rotation of variator shaft 1064 from the inputshaft 1030.

The speed and direction of rotation of the galaxial carrier 1046 andthus the output shaft 1060 is dependent upon the difference intangential velocity of the sun gear 1038 and the internal ring gear1054. The speed of rotation of the internal ring gear 1054 is controlledby the variator system, which adjusts the rotational speed that is takenfrom the input shaft 1030. The sun gear 1038 and the internal ring gear1054 can be caused to rotate oppositely to one another or in the samedirection by, for example, the addition or deletion of a directionreversing gear between the variator gear 1068 and the external ring gear1070. If the sun gear 1038 and the ring gear 1054 are caused to rotatein the same direction, the output speed is the result of the differencebetween the tangential velocity of the sun gear 1038 and the ring gear1054. The output is neutral and free when the sun gear 1038 and ringgear 1054 rotate at the same velocity and in the same direction, thatis, the galaxial carrier can be moved by the application of an externalforce. The galaxial carrier will be locked in place in the neutralposition, however, when the sun gear 1038 and variator shaft 1064 arecaused to rotate in the opposite position. It is also possible in thisembodiment to apply the power input at the ring gear 1054 or at what ispresently referred to as the output shaft 1060.

Variator systems useful with the invention may be of different designs,although pulley and belt systems have been found to effectively transmitpower from the input shaft to the variator shaft. An alternativevariator system according to the invention is shown in FIG. 10. In thisembodiment, the variator system would have a first adjustable pulley2010 having opposing beveled faces 2004 and 2008 mounted on the shaft1012. The pulley face 2004 may be moved longitudinally along the lengthof the shaft 1012 by means of a control. The control may be activated byfluid pressure, electric servo control, or by other means known in theart, such as a mechanical control arm 2014. Adjusting the distancebetween the beveled pulley faces will adjust the effective pulleydiameter encountered by a pulley belt 2018. The adjusted pulley diameterwill change the tangential velocity at which the pulley belt 2018 isdriven.

The pulley belt 2018 also engages a double pulley 2025 on the shaft 974.The pulley 2025 is rotatably mounted about the shaft 974. The pulley2025 has beveled sides 2022 and 2026. A double-sided, beveled pulleymember 2035 is slidably mounted on the pulley 2025 between the beveledsides 2022 and 2026. A pulley face 2030 of the member 2035 opposes thebeveled face 2026 of the pulley 2025 and a beveled face 2024 of themember 2035 opposes the beveled face 2022 of the pulley 2025. The face2026 of the pulley 2025 and face 2030 of the pulley member 2035 engagethe pulley belt 2018. The face 2022 of the pulley 2025 and the face 2024of the pulley member 2035 engage a pulley belt 2040. The pulley belt2040 also engages a variable width pulley 2042 on the shaft 986. Biasingmeans for balancing the tension of the belt 2040, such as spring 2044,can act on a pulley face 2046 which is slidably mounted on the shaft986.

Sliding movement of the pulley member 2035 with respect to the faces2022 and 2026 of the pulley 2025 will increase and decrease theeffective diameter encountered by the pulley belts 2018 and 2040. Theeffective diameter on either side of the pulley member 2035 will dependupon the distance of the pulley member 2035 from the sides of the pulley2025. The closer the pulley member 2035 is to one of the side faces 2022and 2026 of the pulley 2025, the greater will be the effective diameterencountered by a belt therebetween. The effective diameter seen by oneof the belts 2018 and 2040 will therefore increase as the othereffective diameter decreases.

Adjustment of the pulley 2010 by the control arm 2014 will cause anincrease or decrease in the effective diameter of the pulley 2010. Theincreased or decreased tension on the pulley belt 2018 will cause thepulley member 2035 to move away from or toward, respectively, the face2026 of the pulley 2025. Movement of the pulley member 2035 away from ortoward the face 2026 of the pulley 2025 will cause an equal and oppositeresult with respect to the pulley face 2022. This movement will increaseor decrease the tension on the pulley belt 2040, which will decrease orincrease, respectively, the effective diameter of the pulley 2042.Adjustment of the pulley 2010 will thereby affect the rotational speedwhich is transferred from the shaft 1012 to the shaft 986.

Another variator system according to the invention is shown in FIG. 8.In this embodiment, speed control is transferred from the input shaft780 to the variator shaft 790 by means of dual pulley belts 2094 and2098. A pulley 2100 is rotatably mounted on the shaft 780 and includespulley faces 2104 and 2106. A pulley 2108 is rotatably mounted on theshaft 780 and includes pulley faces 2112 and 2114. Pulley face 2104 aslidably mounted on the shaft 780 and its position is biased inward by abiasing means 2118 which may include a biasing member, such as spring2120. Similarly, the pulley face 2112 of pulley 2108 is slidable on theshaft 780 and may include biasing means 2124 which may include a biasingmember, such as spring 2128. Pulley belts 2094 and 2098 engage thepulleys 2100 and 2114 to the variable width pulleys 2130 and 2132,respectively, on the shaft 790. Biasing means such as spring 2134 can beprovided between the pulleys 2130 and 2132 to balance the force of thepulley belts 2094 and 2098. Speed control form the shaft 780 is therebytransferred to the variator shaft 790. It is important that the twobelts 2094 and 2098 move at precisely the same speed to prevent slippageand loss of power. This is accomplished by the provision of a gearedcoupling system between the pulleys 2100 and 2108. The coupling systemincludes a beveled gear 2138 fixed to the pulley face 2106 and a beveledgear 2140 fixed to the pulley face 2114. The gears 2138 and 2140 arefreely rotatable with respect to the shaft 780. Beveled gears 2144 and2148 are rotatably fixed to the shaft 780 through shaft mounts 2152 and2156, respectively and mesh with the beveled gears 2138 and 2140. Thebeveled gears 2144 and 2148 are thereby driven by the shaft 780 and inturn drive each of the pulleys 2100 and 2108 through their associatedgears 2138 and 2140.

The differential coupling between the respective pulleys 2100 and 2108will automatically adjust to keep the speeds of the pulley belts 2094and 2098 at the pulleys 2130 and 2132 nearly identical. The gears 2144and 2148 rotate about the axis of their respective mounts 2152 and 2156and translate around the axis of the shaft 780. The gears 2144 and 2148will not rotate when the pulley belts 2094 and 2098 are of the samelengths and the pulleys 2100 and 2108 have the same effective diameter.The effective diameter of one of the variable width pulleys 2100 and2108 will increase as its corresponding pulley belt loosens. The pulleybelt engaging this greater effective diameter would be carried at agreater velocity than that of the other pulley if the two pulleys wererigidly coupled and thus necessarily rotating at the same angular speed.The geared coupling of the invention will permit the other, smallereffective diameter pulley to rotate at a faster rate than the largerdiameter pulley, to balance the speeds of the belts. The beveled gears2144 and 2148 will begin to rotate about their respective mounts topermit the larger effective diameter pulley to rotate at a slower rateand the smaller effective diameter pulley to rotate at a greater rate. Abalancing effect thereby occurs which tends to equalize the velocity ofthe pulley belts.

It is desirable for proper performance of the transmissions to provideadequate controlling and safety devices. One such system according tothe invention is shown in FIG. 13. The transmission includes an inputshaft 3004 has at its end within the housing 3008 a sun gear 3010. Avariator system is provided to transfer speed control from the inputshaft to a variator shaft 3014. The variator shaft 3014 is rotatablymounted through the housing 3008. A pulley 3018 on the input shaft 3004has beveled pulley faces 3020 and 3022. The face 3020 is preferablyslidable on the input shaft 3004. Biasing means 3024 is preferablyprovided to keep the faces 3020 and 3022 properly spaced with respect tothe tension on a pulley belt 3028 which engages the pulley 3018. Thepulley belt 3028 transfers power from the input shaft 3004 to a pulley3032 on the variator shaft 3014. The pulley 3032 has pulley faces 3034and 3038. The variator shaft 3014 has a variator gear 3042 within thehousing. The variator gear 3042 meshes with an external ring gear 3044on a drum 3045 which is rotatably mounted about an output shaft 3048.The output shaft 3048 is rotatably mounted through the housing 3008 andincludes at its end within the housing 3008 a planetary carrier 3052.Planetary gears 3054 are rotatably mounted on the planetary carrier 3052and mesh between with the sun gear 3010 and an internal ring gear 3058on the drum 3045.

The variator shaft 3014 is preferably tubular and has a control arm 3060extending therethrough. A housing 3062 may be provided at the pulleyface 3034 to operatively connect the control arm 3060 to the pulley face3034. The housing 3062 may have an internal ring or bearing 3063 whichis positioned between raised contact surfaces 3065 and 3067 on thecontrol arm 3060. Movement of the control arm 3060 in either directionthrough the variator shaft 3014 will cause contact between one of thecontact surfaces and the internal ring 3063. The housing 3062 and pulleyface 3034 will then follow the control arm 3060. Biasing means forbalancing the tension of the belt 3028 could optionally be provided in ahousing 3061.

A linkage member 3064 connects the control arm 3060 to a control column3068 which in turn is connected to a suitable control such as a wheel3070. Rotation of the wheel 3070 causes movement of the linkage member3064 such that the control arm 3060 is moved inwardly or outwardlythrough the variator shaft 3014 is moved inwardly or outwardly throughthe variator shaft 3014. A linkage L-member 3074 is pivotally connectedbetween the control arm 3060 and an extension linkage member 3076.Upward or downward movement of the L-member 3074 causes upward ordownward movement of the extension linkage member 3076. The extensionlinkage member 3076 is pivotally connected to a friction member 3080.The friction member 3080 may be annular in shape and is frictionally incontact with the output shaft 3048.

Rotation of the output shaft 3048 acts through friction to carry thefriction member 3080 and, in turn, to move linkage members 3076 and3074, as well as the control arm 3060. Movement of the control arm 3060will move the beveled pulley face 3034 inwardly or outwardly dependingon the direction of rotation of the output shaft 3048. Movement of thepulley face 3034 will vary the effective diameter of the pulley 3032,which will change the speed of rotation of the variator shaft 3014. Thiswill reduce or increase the speed of the counter-rotating internal ringgear 3058 on the drum 3045. This will reduce the difference in speedbetween the counter-rotating internal ring gear 3058 and the sun gear3010. The transmission thereby approaches the neutral position until theoutput shaft 3048 no longer rotates. The frictional force on thefriction member 3080 caused by the rotation of the output shaft 3048will then cease and the transmission will remain in the stable neutralposition. The transmission has automatically found the neutral position.

If, for example, the pulley faces 3034 and 3038 are held close togetherthrough manipulation of the wheel 3070, the effective diameter of thepulley 3032 will increase with respect to that of the pulley 3018. Theinternal ring gear 3058 will rotate at a relatively slower rate, whichis assumed to be in the clockwise direction, than the sun gear 3010 inthe counterclockwise direction. The planetary gears 3054 will thenfollow the faster rotating sun gear 3010, and the output shaft 3048 andits associated gear 3084 will likewise rotate in a counterclockwisedirection at a speed that is proportional to the difference in thetangential velocities of the sun gear 3010 and the ring gear 3058.

If manipulation of the wheel 3070 is ceased, the frictional member 3080will be carried in a counterclockwise direction by the rotation of theoutput shaft 3048. This will move the linkage member 3076 up and thepivot member 3074 toward the input side of the transmission. Thismovement will be conveyed to the control arm 3060, which through itslinkage to the pulley face 3034 will push that face away from the pulleyface 3038. This action will decrease the effective diameter of thepulley 3032, such that for a given rotational speed of the pulley 3018,the pulley 3032 and its associated variator shaft 3014 will rotate morerapidly. The increased rotational speed will be transferred through thevariator gear 3042 to the external ring gear 3044 and the internal ringgear 3058. The tangential velocity of the internal ring gear 3058eventually will approach the tangential velocity of the sun gear 3010 asthis action continues. The transmission will finally reach the neutralposition. The wheel 3070 can be used to override the automaticneutral-finding function when rotation of the output is desired.

It will also be appreciated that, had the rotational direction of theoutput shaft 3048 been opposite to that which was assumed, the action ofthe control would have been in an opposite direction. The frictionalmember 3080 would have been carried in the opposite direction, urgingthe pulley face 3034 inwardly to decrease the rotational speed of theinternal ring gear 3058, again until the neutral position had beenobtained. The transmission thereby provides an automatic neutral-findingsafety control no matter in which direction the output is rotating.

The friction member 3080 will in this embodiment be a constant source offriction on the output shaft when it is rotating. It is thereforedesirable to form this member from a high quality alloy or othermaterial which will not readily wear out. It is also possible to providemeans for selectively engaging the friction member 3080 as by a liquidcontrol.

Another control according to the invention is shown in FIGS. 14-15. Anoutput shaft 3120 is rotatably mounted through a transmission housing3124. A control handle 3134 is rotatably mounted about the output shaft3120 so as to freely engage the output shaft 3120. A friction member3128 is connected to the housing 3124 and biased to frictionally engagethe control handle 3134 so that the control handle 3134 will retain itssetting. A linkage member 3138 operatively connects the control handle3134 to a variable width pulley 3144. The connection of the linkage 3138to the pulley 3144 may be through a tubular extension 3148 at the centerof a pulley face 3140. The tubular extension 3148 fits within a tubularhousing 3154 which extends from an opposing pulley face 3158. Thelinkage 3138 may be secured to the housing 3154 through a bearing 3162and a bushing 3164. Nuts 3168, 3172 and 3176 may engage threadedstructure on the linkage member 3138 and bear against the bushing 3164.The system is easily disconnected to perform adjustments or repairs.

The pulley 3144 may be part of a variator system according to theinvention. Movement of the control handle 3134 will result incorresponding movement of the pulley face 3158 with respect to theopposing pulley face 3140, which will increase or decrease the effectivediameter of the pulley 3144. The change in effective pulley diameter ofa variator pulley will affect the transfer of rotational speed throughthe variator system to either slow or speed the rotation of the outputshaft 3120, as previously described. The linkage member 3138 can beoperatively connected to either the pulley face 3140 or, as shown, thepulley face 3158. The linkage member 3138 can therefore be connected soas to either increase or decrease the effective diameter of the variatorpulley 3144 for a given direction of movement of the linkage member3138.

The control is provided with a neutral finding braking system.Engagement means such as a friction brake pad 3182 is operativelyconnected to the linkage member 3138, as through the control handle3134. The engagement means can frictionally contact a raised brakesurface 3183 on the output shaft 3120. The brake surface 3183 can be asubstantially C-shaped cross section as shown or another suitablesurface. The engagement means could alternatively be other means foroperatively connecting the linkage member 3138 to the motion of theoutput shaft 3120. The brake pad 3182 could, for example, be replaced bya pin which would engage a ratchet or the like on the output shaft 3120.The brake pad 3182 preferably comprises a piston 3186 which is movablethrough a cylinder 3190 formed in the control handle 3134. A fluid ormechanical brake line 3194, which may be connected to a brake pedal 3196or automatic control source 3198, may be used to urge the piston 3186and the associated brake pad 3182 or other engagement means into contactwith the brake surface 3183. The automatic control source may be anengine governor which generates a pneumatic signal in response to enginespeed. When speed control handle 3134 is moved from fast to slow fromeither direction of rotation, it may automatically engage, at its zerooutput or neutral handle position, fluid control (not shown) connectedto line 3198 that automatically engages the frictional member 3182 andthereby activate the neutral finding servo mechanism. Because thisstepless transmission can shift speed and torque without shifting gearsit needs no clutch. It is essential, in many applications, that aclutchless transmission have some positive means for maintaining aneutral or zero output condition. The above disclosed neutral findingservo mechanism provides that means.

A mechanical park brake linkage may also be provided. The mechanicalbrake linkage 3202 may be biased as by spring 3206 to urge the piston3186 and friction pad 3182, or other engagement means, into contact withthe brake surface 3183. The mechanical brake linkage 3202 may besubstantially L-shaped as shown and one leg of the L may rest on ashoulder 3208 of the control handle 3134, thereby preventing engagementwith the piston 3186. The linkage 3202 may be rotated to an alternativeposition (phantom lines) on a lower shoulder 3212 of the control handle3134 to permit engagement of the mechanical brake linkage 3202 with thepiston 3186 and subsequent frictional connection between the frictionpad 3182 and the brake surface 3183.

Engagement of the brake pad 3182 with the brake surface 3183, eitherthrough the action of the pneumatic brake pedal, pneumatic controlsource or the mechanical brake linkage, will cause the control handle3134 to be carried with rotation of the output shaft 3120. This movementwill cause corresponding movement of the control linkage 3138, whichwill adjust the effective diameter of the variator pulley 3144 throughmovement of the pulley face 3140 until the neutral position has bereached.

Connection of the control to a transmission according to the inventionis illustrated in FIG. 8. A control 2230 is mounted to the housing 784at a neck 2236 through which the output shaft 810 is mounted. A linkage2240 is connected to the control 2230 at one end and to a piston 2242 atits other end. The piston 2242 is moveable through a cylinder 2244.Signal line 2248 is operatively connected to the variator system, suchas to the variator pulleys 2130 and 2132 as shown. The variator shaft790 may be tubular such that the signal line 2240 may pass through itscenter. Movement of the control 2230 in one direction or another willgenerate a pressure source which will be communicated through anaperture 2250 to the interior of a fluid containment housing 2254. Thepneumatic signal carried through the signal line 2248 is passed to thehousing 2254 whereby an increase or decrease in pressure will increaseor decrease, respectively, the spacing between opposing pulley faces andthus the effective diameter of the pulleys 2130 and 2132. The adjustedeffective diameters of the pulleys 2130 and 2132 will adjust therotational speed of the variator shaft 790 with respect to that of theinput shaft 780. The speed and direction of rotation of the output shaft810 can thereby be controlled by positioning of the control 2230.

Braking can be effected by engagement means such as a brake pad 2258which can be connected to a piston 2260 in a cylinder 2262. A pneumaticbrake line 2264 may be connected to a brake pedal 2266 or to anothersignal source such as an automatic brake. Pressure through the line 2264will force the piston 2260 and the friction member 2258 against theoutput shaft 810. A raised friction surface 2270 can be provided on theoutput shaft 810 to contact the brake pad 2258. It will be appreciatedthat the large diameter brake surface 2270 will provide greaterfrictional resistance per degree of rotation of the output shaft 810,than would direct application of the brake pad 2258 on the output shaft810.

Engagement of the brake pad 2258 with the friction surface 2270 on theoutput shaft 810 will cause the control 2230 to be carried with therotation of the output shaft 810. This movement will cause the linkage2240 and piston 2242 to create a pressure signal in the signal line2248. The signal will cause corresponding movement of faces 2251 and2253 of the pulleys 2130 and 2132, respectively. This movement willalter the effective diameter of the pulleys 2130 and 2312 so that therotational speed of the variator shaft 790 will be adjusted with respectto the rotational speed of the input shaft 780. The movement will act tobalance the speeds of rotation of the shafts, and thus of the planetarygears 828 and the sun gear 834, until the neutral position has beenfound and movement of the output shaft 810 has essentially stopped.

An alternative control connection to a transmission is shown in FIG. 10.A control 2404 with a handle 2408 is rotatably mounted about a neck 2410of the housing 978. The control 2404 is also mounted about the outputshaft 996 which passes through the neck 2410. A sprocket 2414 isconnected by a chain 2418 to a sprocket 2420. The sprocket 2420 ismounted on a control arm 2014 which may pass through the variator shaft1012. Threads 2422 on the control arm 2014 engage threaded structure2426 on the housing 978 such that rotation of the control arm 2014 willcause inward or outward movement of the control arm 2014 through thevariator shaft 1012. The control arm 2014 is connected to the pulleyface 2004 of the pulley 2010. This connection can be made by a housing2430 on the pulley face 2004, to which is attached the control arm 2014.Movement of the handle 2408 will cause movement of the sprocket 2414,chain 2418, and sprocket 2420. This will cause the control arm 2014 tomove inwardly and outwardly to adjust the effective diameter of thepulley 2010 by adjusting the position of the beveled pulley face 2004with respect to its opposing pulley face 2008. Adjustment of theeffective diameter of this pulley will adjust the rotational speed whichis transferred from the shaft 1012 to the shaft 986.

A braking action can be effected by engagement means such as a frictionpad 2438. The friction pad 2438 is preferably connected to a piston 2440in a cylinder 2442. A signal line 2448 carries pressure signals from abrake pedal 2450 or neutral position of speed control arm 2408 or othercontrol signal source to the cylinder 2442. Increased pressure in thecylinder 2442 will force the friction pad 2438 against a raised frictionsurface 2458 on the output shaft 996. Rotation of the output shaft 996will then carry the handle 2408. Movement of the handle 2408 will causemovement of the sprocket 2414, the chain 2418, and the sprocket 2420.The control arm 2014 will move inwardly or outwardly to adjust theeffective diameter of the pulley 2010. Adjustment of the pulley 2010will balance the speed of rotation of the internal ring gear 984 andtubular sun gear 1004 so that the transmission is brought to neutral,wherein rotation of the output shaft 996 will stop with a correspondingcessation of movement of the handle 2408.

Another control according to the invention is shown in FIG. 16. Anoutput shaft 3304 in a transmission has a raised friction surface 3308which can have a C-shaped cross section, such as that shown in FIGS.14-15. A control handle 3312 is connected to an annular portion 3316.The annular portion 3316 is mounted about the output shaft 3304. Apiston 3320 with a friction pad 3322 at one end is movable through acylinder 3326 in the control handle 3312. A control linkage 3330connects the control handle 3312 to the variator system, for example, toa face of a variator pulley as previously described and shown in FIGS.14-15. Application of the friction pad 3322 to the friction surface 3308on the output shaft 3304 will cause the control handle 3312 and itsassociated linkage 3330 to be carried with the output shaft 3304. Thismovement will result in adjustment of the variator system, as byincreasing the distance between the faces of a variator pulley, to causethe transmission to be urged to the neutral position. This movement willcontinue until the neutral position has been found, whereupon movementof the output shaft 3304 and the control handle 3312 will cease.

Automatic control can be provided. A driver 3340 is connected to apiston 3342 in a cylinder 3344. A control line 3346 receives a pressuresignal from a line 3350 which is connected to a signal generator such asthe piston 3354 and the cylinder 3358. The piston 3354 can beoperatively connected to a suitable means for indicating engine speed,which can be centrifugal, mechanical, pneumatic or vacuum in nature. Thepressure signal transferred through the lines 3350 and 3346 urges orreleases the piston 3342 and the driver 3340. The driver 3340operatively contacts the linkage 3330, as through the handle 3312, suchthat movement of the driver will move the linkage. Movement of thelinkage member 3330 adjusts the effective diameter of a variator pulleyor the like to slow or speed the transmission output as necessary. Theoutput of the transmission is thereby controlled by engine speed.

A shift is provided in the form of a fluid valve 3364 which can bemanipulated by a lever 3368. The valve can include a valve stem 3370with valve stops 3372, 3374, and 3376. The lines 3346 and 3350 areconnected to the valve such that in one position of the lever 3368,fluid can flow through these lines. In another position of the lever3368, the stops block fluid flow through the line 3346 and permitpassage of fluid through an alternate line 3380. The alternate line 3380connects to a cylinder 3384 which has a piston 3386 within. The piston3386 is operatively connected to a driver 3390 which is positioned todrive the linkage 3330, as through the handle 3312, in a directionopposite to the direction which the driver 3340 moves the linkage 3330.One driver can then be used as a forward control and the other as areverse control since the direction in which the linkage 3330 is urgedcan be used to adjust the effective diameter of variator pulley and thusthe speed and direction of rotation of the output shaft. The linkage3330 could also be used to variably adjust other structure including avalve, clutch, or brake system.

Pressure can be released from the system through pressure relief valves3394 and 3396, which relieves high pressures in the fluid lines 3346 and3380, respectively. The pressure relief valve 3396 connects to a line3400 which in turn connects to a fill line 3404. The pressure reliefvalve 3394 is also connected to the fill 3404. Excess fluid through bothof the pressure relief valves is thereby transferred to the line 3404.The fill line 3404 is connected to a fill tank 3408 which supplies fluidto the system or stores excess fluid received from the pressure reliefvalves.

A brake pedal 3410 or the like can be used to manipulate a manual brake.The brake pedal 3410 would urge a piston 3414 in a cylinder 3418 to senda pressure signal through a line 3420. The line 3420 connects with thecylinder 3326. Movement of the brake pedal 3410 will then apply a fluidpressure to the cylinder 3326 and thus to the brake pad 3322 toeffectuate a braking action which will cause the transmission to returnto the neutral position as previously described. It is desirable torelieve the pressure on the drivers 3340 and 3390 to permit a quickresponse to the braking action. This is accomplished by pressure reliefvalves 3428 and 3432. A fluid line 3436 connects the brake line 3420 tothe valve 3432. A fluid line 3440 connects the brake line 3420 to thevalve 3428. Pressure on the brake pedal 3410 opens the valves 3428 and3432 to allow fluid to pass from the lines 3346 and 3380 to the fillline 3404 and the fill tank 3408. Fluid from the line 3380 passes fromthe valve 3432 to the line 3400, which connects to the fill line 3404.Pressure on the drivers 3340 and 3390, through the respective cylinders3344 and 3384, is relieved and the handle 3312 and linkage 3330 canquickly return to the neutral position.

Referring now to FIG. 17, a neutral-seeking servo mechanism of theinvention is illustrated diagrammatically. Raising and lowering controlshaft 4002 operates hydraulic variator valve 4000 which controls thespeed and direction of rotation of the output of hydraulic transmission4001, which is of the type well known in the art. Rack 4003 on shaft4002 is actuated by rotation of pinion 4004 which is rotated by handlever 4005 pivoting from high speed forward as indicated by F onquadrant 4006, through neutral as indicated by N to high speed reverseas indicated by R. The output from the transmission is shaft 4007 withbevel gear 4009 meshing with bevel gear 4010, which is fixed to shaft4011 which rotates differential gears, wheels, tracks, drums or otheroutput devices well known in the art. Splines 4012 on shaft 4011slidably engage clutch 4013. A clutch dog 4016 rides in groove 4014 withbearings 4015 to move the clutch 4012 toward or away from second piniongear 4017 which is rotatably mounted on a shaft 4011. A pair of highfriction clutch faces 4018, one on the clutch 4013 and one on piniongear 4017 are forced tightly together by extension spring 4020 so thatsecond pinion gear 4017 is coupled to shaft 4011. Rack 4027 couples thefirst and second pinion gears together. With extension spring 4020engaging the clutch, the neutral seeking mechanism is activated. Asshown, the output of the transmission is in reverse and bevel gear 4010is rotated in the direction of arrow 4029. Because the clutch 4013 isengaged, pinion gear 4017 is rotated in the same direction. This movesrack 4027 in the direction of arrow 4030 which rotated pinion 4004 inthe same direction as moving the hand control lever 4005 toward theforward position. This causes the variator valve 4000 and transmissionto slow from reverse toward neutral. This continues until neutralcondition is reached. If the transmission goes beyond neutral toforward, then the output rotation will be reversed and the rack 4027will move in the opposite direction until the shaft 4007 ceases torotate in either direction. To disengage the clutch and theneutral-seeking mechanism force must be applied in opposition to spring4020. This clutch-releasing tensile force is applied by actuator 4021.This may be any of the actuators well known in the art includingmechanical linkage, hydraulic, pneumatic, or electric. Shown here is apreferred electric solenoid that may be activated by switch 4024 that isengaged by compression of hand grip 4023. Whenever the operator releasesthe grip, the transmission automatically returns to neutral. Switch 4025is activated by quadrant 4006. Whenever the lever is not in neutralposition, the neutral-seeking mechanism is disengaged. Other connectionsmay also be made to actuator 4021 to control the neutral-seekingmechanism, as exemplified by normally closed switch 4026. This iscoupled to a brake pedal so that application of the brake causes theoutput to move to neutral. The same mechanism may be employed withnon-reversing transmissions to bring the output to neutral.Alternatively, FIG. 17 may represent a transmission 4001 of theplanetary gear type of Fig. 5 with control rod 4002 representing controlrod 398 of FIG. 5.

INDUSTRIAL APPLICABILITY

The transmission of the invention may be employed to drive wheeled andtracked vehicles where a single stepless control of both speed anddirection is desirable. The transmission may be used to power otherrotary devices such as boat propellers, hoist windlass, and power tools.Versatility of control and the elimination of the cost and complexity ofa clutch and reversing gear with their separate controls make theinvention applicable in those devices where a compact structure andeconomy of manufacture and maintenance are important.

The above disclosed invention has a number of particular features whichshould preferably be employed in combination although each is usefulseparately without departure from the scope of the invention. While Ihave shown and described the preferred embodiments of my invention, itwill be understood that the invention may be embodied otherwise than asherein specifically illustrated or described, and that certain changesin the form and arrangement of parts and the specific manner ofpracticing the invention may be made within the underlying idea orprinciples of the invention within the scope of the appended claims.

I claim:
 1. A bidirectional control for a stepless transmission whereinthe speed and direction of rotation of an output shaft is related to thedifference in the rates of rotation of an input shaft and a secondshaft, the input shaft and the second shaft each having associatedtherewith variable width pulley means, and a pulley belt connectedtherebetween, the control comprising:linkage means operatively connectedto at least one of the variable width pulley means and operable toadjust the effective diameter of said pulley means; and controllablebrake means for engaging and disengaging the output shaft; the brakemeans, when engaged, being operatively connected to the linkage meanssuch that rotation of the output shaft will move the linkage and adjustat least one of the variable width pulley means to adjust the rate ofrotation transferred from the input shaft to the second shaft, wherebythe transmission is brought to the neutral position by the rotation ofthe output shaft; the brake means, when disengaged, presenting noresistance to rotation of the output shaft.
 2. In a transmission of thetype having an output whose rotation rate may be continuously varied andreversed by an operator control while an input rotates at an unchangedrate, a neutral-seeking mechanism comprising:a) a bidirectional controlmeans for controlling both the rate and direction of rotation of saidoutput, said control means operatively connected to said transmissionwhereby motion of said control means in a first direction from a firstextreme position to a second extreme position varies said output from amaximum rate of clockwise rotation through progressively slower rates tozero output rotation at an intermediate position of said control meansand then through progressively faster counterclockwise rates to maximumrate at a second extreme position; and b) connecting means for removablyconnecting said bidirectional control means to said output means so thatwhen the connecting means is engaged as the output turns clockwise, itmoves said control means in said first direction toward said secondextreme position and when said output turns counterclockwise it movessaid control means in a second direction away from said second extremeposition to thereby cause said control means to seek said intermediateposition and zero output rotation.
 3. The neutral-seeking mechanismaccording to claim 2, in which said bidirectional control means includesa variable diameter pulley.
 4. The mechanism according to claim 3, inwhich said bidirectional control means includes a planetary gear means.5. The mechanism according to claim 2, in which said connecting meansincludes an operative connection to a brake for automatically engagingsaid connecting means to stop said output from rotating when said brakeis applied.
 6. The mechanism according to claim 2, in which saidconnecting means includes an operative connection to said operatorcontrol, whereby movement of said operator control to neutral engagessaid connecting means to stop said output from rotating.
 7. Themechanism according to claim 2, further comprising sensing means forsensing a particular operator activity, said sensing means operativelyattached to said connecting means whereby said connecting means connectssaid control means to said output means when said operator is notengaging in said activity and said connecting means is disconnected whensaid operator is engaging in said activity.
 8. The mechanism accordingto claim 2, in which said connecting means includes hydraulic elements.9. The mechanism according to claim 2, in which said control connectingmeans includes electric elements.
 10. The mechanism according to claim2, in which said bidirectional control means includes elements selectedfrom the group including hydraulic and pneumatic elements.
 11. Themechanism according to claim 2, in which said bidirectional controlmeans includes electric elements.
 12. The mechanism according to claim2, in which said connecting means has two selectable modes ofconnecting, a first mode wherein said connection is made to preventrelative motion between said control means and said output and a secondmode wherein relative motion between said control means and said outputis allowed.
 13. In a transmission of the type having an output whoserotation rate may be continuously varied by an operator control while aninput rotates at an unchanged rate, a neutral-seeking mechanismcomprising:a) a control means for controlling the rate of rotation ofsaid output, said control means operatively connected to saidtransmission whereby motion of said control means in a first directionfrom a first extreme position to a second extreme position varies saidoutput from a maximum rate of rotation through progressively slowerrates to zero output rotation at a second extreme position; and b)connecting means for removable connecting said control means to outputmeans so that when the connecting means is engaged as the said outputturns, it moves said control means in said first direction to saidsecond extreme position thereby achieving zero output rotation.
 14. Theneutral-seeking mechanism according to claim 13, in which said controlmeans includes a variable diameter pulley.
 15. The mechanism accordingto claim 14, in which said control means includes a planetary gearmeans.
 16. The mechanism according to claim 13, in which said connectingmeans includes an operative connection to a brake for automaticallyengaging said connecting means to stop said output from rotating whensaid brake is applied.
 17. The mechanism according to claim 13, in whichsaid connecting means includes an operative connection to said operatorcontrol, whereby movement of said operator control to neutral engagessaid connecting means to stop said output from rotating.
 18. Themechanism according to claim 13, further comprising sensing means forsensing a particular operator activity, said sensing means operativelyattached to said connecting means whereby said connecting means connectssaid control means to said output means when said operator is notengaging in said activity and said connecting means is disconnected whensaid operator is engaging in said activity.
 19. The mechanism accordingto claim 13, in which said control connecting means includes hydraulicelements.
 20. The mechanism according to claim 13, in which said controlconnecting means includes electric elements.
 21. The mechanism accordingto claim 13, in which said control means includes elements selected fromthe group including hydraulic and pneumatic elements.
 22. The mechanismaccording to claim 13, in which said control means includes electricelements.
 23. The mechanism according to claim 13, in which saidconnecting means has two selectable modes of connecting, a first modewherein said connection is made to prevent relative motion between saidcontrol means and said output and a second mode wherein relative motionbetween said control means and said output is allowed.